Extended Translation Editor is a property editor for TsiLang's ExtendedTranslations property. This includes components' non-string properties, such as Left, Right, Width, Tag, Align etc. as well as all properties of any sub-level components such as TLabeledEdit. This could be very useful, for instance, for repositioning or rescaling controls, when you translate your application into a language with phrase length more than in original language.

Translating
To include a component's property into the list of translated properties:

1. Find the component in the Available Properties TreeView (left side of the window), expand the node (pressing the 'plus' sign at the left of the node), then select the property to be translated.
2. Move the property to the Selected Properties list (center of the window), pressing the > (right arrow) button or double-clicking the property.
3. Select it in the Selected Properties list and enter the translations into the Translations grid (right-side of the window) for every language in a manner you used to do in Delphi Object Inspector.
To remove a property from the Selected Properties list select it and press the < (left arrow) button. Press the << (double left arrow) button to remove all the properties at a time.

Then I suggest you the following:
Just save the form to SIL file using TsiLang Expert and your ExtendedTranslations will be saved to the files as well. When loading use LoadAllFromFile and ExtendedTranslations will be loaded as well at run-time.